A customer equipment (CE), e.g. a Digital Subscriber Line (DSL) router at the premises of a fixed-line subscriber, maintains a layer-2 connection with a broadband network gateway (BNG) hosting services, e.g., an Internet access. In order to achieve BNG redundancy for a plurality of CEs, each of multiple BNGs would have to precautionarily maintain a layer-2 connection with each of the CEs. Since the number of connections scales quadratically with system size, this is an inefficient way of realizing redundancy in terms of scalability, maintenance and provisioning.
Existing architectures for customer networks further include an access node (e.g., a DSL Access Multiplexer, DSLAM) functioning as an ATM or Ethernet aggregator that cross-connects the layer-2 interface from the CEs to the layer-2 interface of the BNG. The traffic aggregated from the access nodes is steered to the BNG as an IP node. Point-to-point sessions are established between the CE and the BNG, e.g., using the Point-to-Point Protocol (PPP) over Ethernet (PPPoE), which ensures that all PPPoE frames sent on the wire reach the other end.
However, for realizing redundancy when the access node is connected to the BNG using a layer-2 connection in a transport network, point-to-point or point to multipoint links would have to be provided in the transport network for each of the CEs. Therefore, current BNG deployments implement no node redundancy or a 1+1 BNG redundancy. The latter is far away from being an optimal redundancy solution in terms of cost efficiency and flexibility. Moreover, no automatic load balancing can be done between the BNGs for newly connecting CEs.